There is an urgent need to develop novel, cost-effective manufacturing processes to produce therapeutic antibodies commercially in order to reduce the high manufacturing expenses as well as to address the potential for limited manufacturing capacity. The long-term objectives of this application are to develop novel manufacturing processes using transgenic plants to significantly lower the up-front capital investment and processing costs, shorten the product development cycle, and provide products with superior safety profiles. These objectives are best achieved by utilizing the high-yield transgenic lettuce expression system developed under the funding of the Phase I proposal. In this Phase II plan, transgenic lettuce producing a model antibody will be used to evaluate the scalability of the process and quality of the product from a larger scale pilot production. The same model antibody produced in standard mammalian cell culture will be used for all of comparisons. This model antibody is a fully humanized IgG1? anti-tissue factor antibody (hOAT) that is currently in pre-clinical development as an anti-cancer therapeutic. The specific aims of this research proposal are to: 1) generate 200-kg of transgenic hOAT lettuce biomass using hydroponic production in a greenhouse setting; 2) establish a scalable protein purification method to generate highly purified hOAT from transgenic lettuce; and 3) evaluate lot-to-lot consistency of the plant-derived hOAT using in-vitro and in-vivo testing and further establish its comparability to mammalian cell-produced hOAT. The lower production and capital costs, shortened product development cycle, greater flexibility and scalability, and improved safety of using transgenic lettuce expression methods provides significant value and appeal to this platform for manufacturing therapeutic and diagnostic antibody products. The lower cost of goods would enable wider spread use of antibody therapeutics, particularly in less economically developed markets. The rapidly develop transgenic lettuce capable of producing kilogram quantities of functional recombinant antibody is well suited for biodefense applications where stockpiles of therapeutic proteins are needed to address numerous and continuously changing threats. The use of hOAT as model protein will provide proof-of-principle, demonstrate favorable production economics and confirm antibody functionality/efficacy. It could also lead to the advance of a plant-derived antibody into clinical studies against cancer indications. 7. Project Narrative The goal of this proposal is to develop a novel, cost-effective manufacturing process to commercially produce therapeutic antibodies using transgenic lettuce. The lower cost of goods and better safety profiles of these products would enable broader use of antibody therapeutics, particularly in less economically developed markets and for biodefense purposes. The lettuce-produced model antibody used in this study could also be advanced into clinical development against cancer. [unreadable] [unreadable] [unreadable]